[dragonfly.git] / sys / vm / vm_swapcache.c

/*
 * Copyright (c) 2010 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Implement the swapcache daemon.  When enabled swap is assumed to be
 * configured on a fast storage device such as a SSD.  Swap is assigned
 * to clean vnode-backed pages in the inactive queue, clustered by object
 * if possible, and written out.  The swap assignment sticks around even
 * after the underlying pages have been recycled.
 *
 * The daemon manages write bandwidth based on sysctl settings to control
 * wear on the SSD.
 *
 * The vnode strategy code will check for the swap assignments and divert
 * reads to the swap device.
 *
 * This operates on both regular files and the block device vnodes used by
 * filesystems to manage meta-data.
 */

#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/kthread.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
#include <sys/vmmeter.h>
#include <sys/sysctl.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <sys/lock.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_pageout.h>
#include <vm/vm_pager.h>
#include <vm/swap_pager.h>
#include <vm/vm_extern.h>

#include <sys/thread2.h>
#include <vm/vm_page2.h>

#define INACTIVE_LIST	(&vm_page_queues[PQ_INACTIVE].pl)

/* the kernel process "vm_pageout"*/
static void vm_swapcached (void);
static void vm_swapcached_flush (vm_page_t m);
struct thread *swapcached_thread;

static struct kproc_desc swpc_kp = {
	"swapcached",
	vm_swapcached,
	&swapcached_thread
};
SYSINIT(swapcached, SI_SUB_KTHREAD_PAGE, SI_ORDER_SECOND, kproc_start, &swpc_kp)

SYSCTL_NODE(_vm, OID_AUTO, swapcache, CTLFLAG_RW, NULL, NULL);

int vm_swapcache_read_enable;
static int vm_swapcache_sleep;
static int vm_swapcache_maxlaunder = 256;
static int vm_swapcache_data_enable = 0;
static int vm_swapcache_meta_enable = 0;
static int64_t vm_swapcache_curburst = 1000000000LL;
static int64_t vm_swapcache_maxburst = 1000000000LL;
static int64_t vm_swapcache_accrate = 1000000LL;
static int64_t vm_swapcache_write_count;

SYSCTL_INT(_vm_swapcache, OID_AUTO, maxlaunder,
	CTLFLAG_RW, &vm_swapcache_maxlaunder, 0, "");

SYSCTL_INT(_vm_swapcache, OID_AUTO, data_enable,
	CTLFLAG_RW, &vm_swapcache_data_enable, 0, "");
SYSCTL_INT(_vm_swapcache, OID_AUTO, meta_enable,
	CTLFLAG_RW, &vm_swapcache_meta_enable, 0, "");
SYSCTL_INT(_vm_swapcache, OID_AUTO, read_enable,
	CTLFLAG_RW, &vm_swapcache_read_enable, 0, "");

SYSCTL_QUAD(_vm_swapcache, OID_AUTO, curburst,
	CTLFLAG_RW, &vm_swapcache_curburst, 0, "");
SYSCTL_QUAD(_vm_swapcache, OID_AUTO, maxburst,
	CTLFLAG_RW, &vm_swapcache_maxburst, 0, "");
SYSCTL_QUAD(_vm_swapcache, OID_AUTO, accrate,
	CTLFLAG_RW, &vm_swapcache_accrate, 0, "");
SYSCTL_QUAD(_vm_swapcache, OID_AUTO, write_count,
	CTLFLAG_RW, &vm_swapcache_write_count, 0, "");

/*
 * vm_swapcached is the high level pageout daemon.
 */
static void
vm_swapcached(void)
{
	struct vm_page marker;
	vm_object_t object;
	struct vnode *vp;
	vm_page_t m;
	int count;

	/*
	 * Thread setup
	 */
	curthread->td_flags |= TDF_SYSTHREAD;

	/*
	 * Initialize our marker
	 */
	bzero(&marker, sizeof(marker));
	marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER;
	marker.queue = PQ_INACTIVE;
	marker.wire_count = 1;

	crit_enter();
	TAILQ_INSERT_HEAD(INACTIVE_LIST, &marker, pageq);

	for (;;) {
		/*
		 * Loop once a second or so looking for work when enabled.
		 */
		if (vm_swapcache_data_enable == 0 &&
		    vm_swapcache_meta_enable == 0) {
			tsleep(&vm_swapcache_sleep, 0, "csleep", hz * 5);
			continue;
		}

		/*
		 * Polling rate when enabled is 10 hz.  Deal with write
		 * bandwidth limits.
		 *
		 * We don't want to nickle-and-dime the scan as that will
		 * create unnecessary fragmentation.
		 */
		tsleep(&vm_swapcache_sleep, 0, "csleep", hz / 10);
		vm_swapcache_curburst += vm_swapcache_accrate / 10;
		if (vm_swapcache_curburst > vm_swapcache_maxburst)
			vm_swapcache_curburst = vm_swapcache_maxburst;
		if (vm_swapcache_curburst < vm_swapcache_accrate)
			continue;

		/*
		 * Don't load any more into the cache once we have exceeded
		 * 3/4 of available swap space.  XXX need to start cleaning
		 * it out, though vnode recycling will accomplish that to
		 * some degree.
		 */
		if (vm_swap_cache_use > vm_swap_max * 3 / 4)
			continue;

		/*
		 * Calculate the number of pages to test.  We don't want
		 * to get into a cpu-bound loop.
		 */
		count = vmstats.v_inactive_count;
		if (count > vm_swapcache_maxlaunder)
			count = vm_swapcache_maxlaunder;

		/*
		 * Scan the inactive queue from our marker to locate
		 * suitable pages to push to the swap cache.
		 *
		 * We are looking for clean vnode-backed pages.
		 *
		 * NOTE: PG_SWAPPED pages in particular are not part of
		 *	 our count because once the cache stabilizes we
		 *	 can end up with a very high datarate of VM pages
		 *	 cycling from it.
		 */
		m = &marker;
		while ((m = TAILQ_NEXT(m, pageq)) != NULL && count--) {
			if (m->flags & (PG_MARKER | PG_SWAPPED)) {
				++count;
				continue;
			}
			if (vm_swapcache_curburst < 0)
				break;
			if (m->flags & (PG_BUSY | PG_UNMANAGED))
				continue;
			if (m->busy || m->hold_count || m->wire_count)
				continue;
			if (m->valid != VM_PAGE_BITS_ALL)
				continue;
			if (m->dirty & m->valid)
				continue;
			if ((object = m->object) == NULL)
				continue;
			if (object->type != OBJT_VNODE ||
			    (object->flags & OBJ_DEAD)) {
				continue;
			}
			vm_page_test_dirty(m);
			if (m->dirty & m->valid)
				continue;
			vp = object->handle;
			if (vp == NULL)
				continue;
			switch(vp->v_type) {
			case VREG:
				if (vm_swapcache_data_enable == 0)
					continue;
				break;
			case VCHR:
				if (vm_swapcache_meta_enable == 0)
					continue;
				break;
			default:
				continue;
			}

			/*
			 * Ok, move the marker and soft-busy the page.
			 */
			TAILQ_REMOVE(INACTIVE_LIST, &marker, pageq);
			TAILQ_INSERT_AFTER(INACTIVE_LIST, m, &marker, pageq);

			/*
			 * Assign swap and initiate I/O
			 */
			vm_swapcached_flush(m);

			/*
			 * Setup for next loop using marker.
			 */
			m = &marker;
		}

		/*
		 * Cleanup marker position.  If we hit the end of the
		 * list the marker is placed at the tail.  Newly deactivated
		 * pages will be placed after it.
		 *
		 * Earlier inactive pages that were dirty and become clean
		 * are typically moved to the end of PQ_INACTIVE by virtue
		 * of vfs_vmio_release() when they become unwired from the
		 * buffer cache.
		 */
		TAILQ_REMOVE(INACTIVE_LIST, &marker, pageq);
		if (m)
			TAILQ_INSERT_BEFORE(m, &marker, pageq);
		else
			TAILQ_INSERT_TAIL(INACTIVE_LIST, &marker, pageq);

	}
	TAILQ_REMOVE(INACTIVE_LIST, &marker, pageq);
	crit_exit();
}

/*
 * Flush the specified page using the swap_pager.
 */
static
void
vm_swapcached_flush(vm_page_t m)
{
	vm_object_t object;
	int rtvals;

	vm_page_io_start(m);
	vm_page_protect(m, VM_PROT_READ);

	object = m->object;
	vm_object_pip_add(object, 1);
	swap_pager_putpages(object, &m, 1, FALSE, &rtvals);
	vm_swapcache_write_count += PAGE_SIZE;
	vm_swapcache_curburst -= PAGE_SIZE;

	if (rtvals != VM_PAGER_PEND) {
		vm_object_pip_wakeup(object);
		vm_page_io_finish(m);
	}
}
Commit	Line	Data
096e95c0 MD	1	/*
	2	* Copyright (c) 2010 The DragonFly Project. All rights reserved.
	3	*
	4	* This code is derived from software contributed to The DragonFly Project
	5	* by Matthew Dillon <dillon@backplane.com>
	6	*
	7	* Redistribution and use in source and binary forms, with or without
	8	* modification, are permitted provided that the following conditions
	9	* are met:
	10	*
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in
	15	* the documentation and/or other materials provided with the
	16	* distribution.
	17	* 3. Neither the name of The DragonFly Project nor the names of its
	18	* contributors may be used to endorse or promote products derived
	19	* from this software without specific, prior written permission.
	20	*
	21	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	22	* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	23	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
	24	* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
	25	* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
	26	* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
	27	* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	28	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
	29	* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	30	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
	31	* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	32	* SUCH DAMAGE.
	33	*/
	34
	35	/*
	36	* Implement the swapcache daemon. When enabled swap is assumed to be
	37	* configured on a fast storage device such as a SSD. Swap is assigned
	38	* to clean vnode-backed pages in the inactive queue, clustered by object
	39	* if possible, and written out. The swap assignment sticks around even
	40	* after the underlying pages have been recycled.
	41	*
	42	* The daemon manages write bandwidth based on sysctl settings to control
	43	* wear on the SSD.
	44	*
	45	* The vnode strategy code will check for the swap assignments and divert
	46	* reads to the swap device.
	47	*
	48	* This operates on both regular files and the block device vnodes used by
	49	* filesystems to manage meta-data.
	50	*/
	51
	52	#include "opt_vm.h"
	53	#include <sys/param.h>
	54	#include <sys/systm.h>
	55	#include <sys/kernel.h>
	56	#include <sys/proc.h>
	57	#include <sys/kthread.h>
	58	#include <sys/resourcevar.h>
	59	#include <sys/signalvar.h>
	60	#include <sys/vnode.h>
	61	#include <sys/vmmeter.h>
	62	#include <sys/sysctl.h>
	63
	64	#include <vm/vm.h>
65	#include <vm/vm_param.h>
66	#include <sys/lock.h>
67	#include <vm/vm_object.h>
68	#include <vm/vm_page.h>
69	#include <vm/vm_map.h>
70	#include <vm/vm_pageout.h>
71	#include <vm/vm_pager.h>
72	#include <vm/swap_pager.h>
73	#include <vm/vm_extern.h>
74
75	#include <sys/thread2.h>
76	#include <vm/vm_page2.h>
77
78	#define INACTIVE_LIST (&vm_page_queues[PQ_INACTIVE].pl)
79
80	/* the kernel process "vm_pageout"*/
81	static void vm_swapcached (void);
82	static void vm_swapcached_flush (vm_page_t m);
83	struct thread *swapcached_thread;
84
85	static struct kproc_desc swpc_kp = {
86	"swapcached",
87	vm_swapcached,
88	&swapcached_thread
89	};
90	SYSINIT(swapcached, SI_SUB_KTHREAD_PAGE, SI_ORDER_SECOND, kproc_start, &swpc_kp)
91
92	SYSCTL_NODE(_vm, OID_AUTO, swapcache, CTLFLAG_RW, NULL, NULL);
93
c504e38e	94	int vm_swapcache_read_enable;
096e95c0	95	static int vm_swapcache_sleep;
1e5196f0	96	static int vm_swapcache_maxlaunder = 256;
096e95c0 MD	97	static int vm_swapcache_data_enable = 0;
096e95c0 MD	98	static int vm_swapcache_meta_enable = 0;
c504e38e MD	99	static int64_t vm_swapcache_curburst = 1000000000LL;
	100	static int64_t vm_swapcache_maxburst = 1000000000LL;
	101	static int64_t vm_swapcache_accrate = 1000000LL;
096e95c0 MD	102	static int64_t vm_swapcache_write_count;
	103
	104	SYSCTL_INT(_vm_swapcache, OID_AUTO, maxlaunder,
	105	CTLFLAG_RW, &vm_swapcache_maxlaunder, 0, "");
c504e38e	106
096e95c0 MD	107	SYSCTL_INT(_vm_swapcache, OID_AUTO, data_enable,
	108	CTLFLAG_RW, &vm_swapcache_data_enable, 0, "");
	109	SYSCTL_INT(_vm_swapcache, OID_AUTO, meta_enable,
	110	CTLFLAG_RW, &vm_swapcache_meta_enable, 0, "");
c504e38e MD	111	SYSCTL_INT(_vm_swapcache, OID_AUTO, read_enable,
	112	CTLFLAG_RW, &vm_swapcache_read_enable, 0, "");
	113
	114	SYSCTL_QUAD(_vm_swapcache, OID_AUTO, curburst,
	115	CTLFLAG_RW, &vm_swapcache_curburst, 0, "");
	116	SYSCTL_QUAD(_vm_swapcache, OID_AUTO, maxburst,
	117	CTLFLAG_RW, &vm_swapcache_maxburst, 0, "");
	118	SYSCTL_QUAD(_vm_swapcache, OID_AUTO, accrate,
	119	CTLFLAG_RW, &vm_swapcache_accrate, 0, "");
096e95c0 MD	120	SYSCTL_QUAD(_vm_swapcache, OID_AUTO, write_count,
	121	CTLFLAG_RW, &vm_swapcache_write_count, 0, "");
	122
	123	/*
	124	* vm_swapcached is the high level pageout daemon.
	125	*/
	126	static void
	127	vm_swapcached(void)
	128	{
	129	struct vm_page marker;
	130	vm_object_t object;
c504e38e	131	struct vnode *vp;
096e95c0 MD	132	vm_page_t m;
	133	int count;
	134
	135	/*
	136	* Thread setup
	137	*/
	138	curthread->td_flags \|= TDF_SYSTHREAD;
	139
	140	/*
	141	* Initialize our marker
	142	*/
	143	bzero(&marker, sizeof(marker));
	144	marker.flags = PG_BUSY \| PG_FICTITIOUS \| PG_MARKER;
	145	marker.queue = PQ_INACTIVE;
	146	marker.wire_count = 1;
	147
	148	crit_enter();
	149	TAILQ_INSERT_HEAD(INACTIVE_LIST, &marker, pageq);
	150
	151	for (;;) {
	152	/*
	153	* Loop once a second or so looking for work when enabled.
	154	*/
	155	if (vm_swapcache_data_enable == 0 &&
	156	vm_swapcache_meta_enable == 0) {
	157	tsleep(&vm_swapcache_sleep, 0, "csleep", hz * 5);
	158	continue;
	159	}
c504e38e MD	160
	161	/*
	162	* Polling rate when enabled is 10 hz. Deal with write
	163	* bandwidth limits.
	164	*
	165	* We don't want to nickle-and-dime the scan as that will
	166	* create unnecessary fragmentation.
	167	*/
	168	tsleep(&vm_swapcache_sleep, 0, "csleep", hz / 10);
	169	vm_swapcache_curburst += vm_swapcache_accrate / 10;
	170	if (vm_swapcache_curburst > vm_swapcache_maxburst)
	171	vm_swapcache_curburst = vm_swapcache_maxburst;
	172	if (vm_swapcache_curburst < vm_swapcache_accrate)
	173	continue;
	174
	175	/*
	176	* Don't load any more into the cache once we have exceeded
1e5196f0	177	* 3/4 of available swap space. XXX need to start cleaning
c504e38e MD	178	* it out, though vnode recycling will accomplish that to
	179	* some degree.
	180	*/
1e5196f0	181	if (vm_swap_cache_use > vm_swap_max * 3 / 4)
c504e38e	182	continue;
096e95c0 MD	183
	184	/*
	185	* Calculate the number of pages to test. We don't want
	186	* to get into a cpu-bound loop.
	187	*/
	188	count = vmstats.v_inactive_count;
	189	if (count > vm_swapcache_maxlaunder)
	190	count = vm_swapcache_maxlaunder;
	191
	192	/*
	193	* Scan the inactive queue from our marker to locate
	194	* suitable pages to push to the swap cache.
	195	*
	196	* We are looking for clean vnode-backed pages.
5ac04117 MD	197	*
	198	* NOTE: PG_SWAPPED pages in particular are not part of
	199	* our count because once the cache stabilizes we
	200	* can end up with a very high datarate of VM pages
	201	* cycling from it.
096e95c0 MD	202	*/
	203	m = &marker;
	204	while ((m = TAILQ_NEXT(m, pageq)) != NULL && count--) {
5ac04117	205	if (m->flags & (PG_MARKER \| PG_SWAPPED)) {
096e95c0 MD	206	++count;
	207	continue;
	208	}
c504e38e MD	209	if (vm_swapcache_curburst < 0)
c504e38e MD	210	break;
5ac04117	211	if (m->flags & (PG_BUSY \| PG_UNMANAGED))
096e95c0 MD	212	continue;
	213	if (m->busy \|\| m->hold_count \|\| m->wire_count)
	214	continue;
	215	if (m->valid != VM_PAGE_BITS_ALL)
	216	continue;
	217	if (m->dirty & m->valid)
	218	continue;
	219	if ((object = m->object) == NULL)
	220	continue;
c504e38e MD	221	if (object->type != OBJT_VNODE \|\|
c504e38e MD	222	(object->flags & OBJ_DEAD)) {
096e95c0	223	continue;
c504e38e	224	}
096e95c0 MD	225	vm_page_test_dirty(m);
	226	if (m->dirty & m->valid)
	227	continue;
c504e38e MD	228	vp = object->handle;
	229	if (vp == NULL)
	230	continue;
	231	switch(vp->v_type) {
	232	case VREG:
	233	if (vm_swapcache_data_enable == 0)
	234	continue;
	235	break;
	236	case VCHR:
	237	if (vm_swapcache_meta_enable == 0)
	238	continue;
	239	break;
	240	default:
	241	continue;
	242	}
096e95c0 MD	243
	244	/*
	245	* Ok, move the marker and soft-busy the page.
	246	*/
	247	TAILQ_REMOVE(INACTIVE_LIST, &marker, pageq);
	248	TAILQ_INSERT_AFTER(INACTIVE_LIST, m, &marker, pageq);
	249
	250	/*
	251	* Assign swap and initiate I/O
	252	*/
	253	vm_swapcached_flush(m);
	254
	255	/*
	256	* Setup for next loop using marker.
	257	*/
	258	m = &marker;
	259	}
1e5196f0 MD	260
	261	/*
	262	* Cleanup marker position. If we hit the end of the
	263	* list the marker is placed at the tail. Newly deactivated
	264	* pages will be placed after it.
	265	*
	266	* Earlier inactive pages that were dirty and become clean
	267	* are typically moved to the end of PQ_INACTIVE by virtue
	268	* of vfs_vmio_release() when they become unwired from the
	269	* buffer cache.
	270	*/
096e95c0 MD	271	TAILQ_REMOVE(INACTIVE_LIST, &marker, pageq);
	272	if (m)
	273	TAILQ_INSERT_BEFORE(m, &marker, pageq);
	274	else
1e5196f0	275	TAILQ_INSERT_TAIL(INACTIVE_LIST, &marker, pageq);
096e95c0 MD	276
	277	}
	278	TAILQ_REMOVE(INACTIVE_LIST, &marker, pageq);
	279	crit_exit();
	280	}
	281
	282	/*
	283	* Flush the specified page using the swap_pager.
	284	*/
	285	static
	286	void
	287	vm_swapcached_flush(vm_page_t m)
	288	{
	289	vm_object_t object;
	290	int rtvals;
	291
	292	vm_page_io_start(m);
	293	vm_page_protect(m, VM_PROT_READ);
	294
	295	object = m->object;
	296	vm_object_pip_add(object, 1);
	297	swap_pager_putpages(object, &m, 1, FALSE, &rtvals);
c504e38e MD	298	vm_swapcache_write_count += PAGE_SIZE;
c504e38e MD	299	vm_swapcache_curburst -= PAGE_SIZE;
096e95c0 MD	300
	301	if (rtvals != VM_PAGER_PEND) {
	302	vm_object_pip_wakeup(object);
	303	vm_page_io_finish(m);
	304	}
	305	}